Sardine Sandwich Bake

12 bread slices, crusts removed
2 tbsp melted butter
2 c grated process sharp cheddar cheese
1 can small sardines
1 small onion, minced
1 c milk
1 tsp salt
1/2 tsp dry mustard
1/4 tsp Worcestershire
1/8 tsp pepper
2 eggs

Heat oven to 350 degrees
In casserole dish, arrange 6 bread slices. Brush the slices with half of the butter and sprinkle with cheese. Arrange drained sardines over cheese. Sprinkle with onion, and the rest of the butter. Cover with remaining bread.
In small bowl combine milk and dry ingredients. Beat in eggs. Pour over sandwiches.
Bake, uncovered, for 40 minutes or until browned.